Field of the Invention
The present invention is directed to an improved fuel rod cladding for a nuclear reactor core. In particular, the present invention is directed to a fuel rod cladding comprising molybdenum and having an outer protective layer and an optional inner layer.
Description of Related Art
Current zirconium alloy (Zr-alloy) fuel cladding for light water reactor fuel rods has been optimized to achieve highly reliable performance during normal operations. However, in severe loss-of-coolant accidents, Zr-alloy cladding has certain high-temperature properties that do not favor its ability to maintain fuel rod integrity. For example, Zr-alloy cladding will undergo rapid oxidation or corrosion in high pressure steam, producing intense heat and hydrogen as the fuel cladding temperature exceeds 700-800° C. Above ˜850° C., Zr-alloy cladding will suffer loss of tensile strength leading to rod burst or defamation, which can impact core coolability. Therefore, during a loss-of-coolant accident the limitations of current Zr-alloy cladding may lead to significant damage and hydrogen generation. However, neither the rapid oxidation or corrosion nor the loss of strength can be avoided by modification of the Zr-alloy cladding composition. Accordingly, there is a need for a fuel rod cladding that minimizes core damage, hydrogen generation, and dispersion of fission products in a severe accident.